> One problem in Linux 2.2 is that kernel threads reload their VM on> context switch (that would include the nfsd thread), this should be> fixed in 2.4 with lazy mm. Hmm actually it should be only fixed for> true kernel threads that have been started with kernel_thread(), the> "pseudo kernel threads" like nfsd uses probably do not get that> optimization because they don't set their MM to init_mm.

yes, but for this there is an explicit mechanizm to lazy-MM during lengthysystem calls, an example is in buffer.c:

> > to get disproportiantely higher in Linux than NetWare 5.x and when it hits> > 60% of total clock cycles, Linux starts dropping off. NetWare 5.x is 1/8 > > I think that can be explained by the copying.

yes. Constant copying contaminates the L1/L2 caches and creates dirtycachelines all around the place. Fixed in 2.4 + TUX ;-)

Ingo

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